The Molecular Diagnostic Core will continue to provide real-time molecular diagnosis for MSLT-II sentinel lymph nodes (SLN) and support the projects of the Program Projects. The major function will be to continue the real-time molecular staging of histopathology(-) SLN of MSLT-II patients for treatment stratification from international and domestic participating sites. To accomplish this major task, the Core will be responsible for processing, purifying, quantifying, cryopreserving, as well as performing multimarker (MM) quantitative realtime RT-PCR (qRT-PCR) assays on MSLT-II paraffin-embedded (PE) SLNs. The results will be immediately utilized by Core B to randomize patients to either the complete lymph node dissection (CLND) arm or routine follow-up arm of the MSLT-II protocol. Results of the MM qRT-PCR SLN staging are provided to Project III and Core A for assessment as well. The Cores other important functions will be the procurement and isolation of DNA/RNA from PE SLN, non-SLN, primary melanomas and systemic metastasis. Specimens will be accrued from JWCI, and MSLT-I & -II for Projects. The main objective is to provide a centralized Molecular Core facility for processing and storage of RNA and DNA extracted from archival PE/frozen specimens and bloods. To ensure the integrity of samples and the meaningfulness of analysis, the operation and implementation of standard operating procedures (SOPS) for specimen handling, processing, cryostorage, and inventory must be centralized. The Core will offer laser capture microdissection and immunohistochemistry services. Prospectively collected blood from MSLT-II patients will be processed for RNA lysates and DNA, allowing for examination of circulating tumor cells from RNA lysates and circulating tumor-related DNA in serum/plasma, repectively, for Project II. The Core will have a quality assurance program for specimen nucleic acid processing and MM qRT-PCR analysis of MSLT-II SLNs. There will be a central laboratory program for the operation of these multiple tasks. The specimens procured from both MSLT-I & -II patients are invaluable resources for this proposal and future molecular studies.